The U.S. National Reconnaissance Office (NRO) successfully launched a classified payload and a dozen experimental cubesats aboard an Atlas 5 rocket Dec. 5 from Vandenberg Air Force Base, Calif.

Denver-based United Launch Alliance conducted the launch on behalf of the NRO, the Chantilly, Va.-based federal agency responsible for the design, construction and operation of the country’s intelligence-gathering satellites.

Because the NRO mission is classified, very few details about the launch or the payload’s purpose are publicly released.

“This launch adds another powerful tool to the nation’s national security toolkit. It once again demonstrates the efficiencies of CubeSat rideshare on an NRO mission,” Air Force Col. Clint Hunt, director of the NRO’s Office of Space Launch, said in a prepared statement. “I couldn’t be more pleased and proud of the combined government and contractor launch team,” 

The rocket carried the Government Experimental Multi-Satellite rideshare payload, which deployed 12 cubesats. Seven of those mini-satellites were sponsored by the NRO; five were sponsored by NASA. 

The launch was the second of two for the NRO in 2013. The next is scheduled for March 2014 from Cape Canaveral Air Force Station, Fla.